Method of forming heat resistant ferrous alloys



y 5, 1943. A. T. CAPE. m 2,319,977

METHOD OF FORMING HEAT RESISIAN I FERROUS ALLOYS Filed May 26, 1942 FIGZ.

FIG.4.

INVENTORS ARTHUR T. CAPE and ANTONE GAXIOLA BY AZMWMOMV ATTORNEY Patented May 25, 1943 UNITED STATES PATENT OFFICE METHOD OF FORMING HEAT ItESISTANT x FERROUS ALLOYS Arthur T. Cape and Antone Gaxiola, Santa Cruz, Calif., assignors to Coast Metals, Inc., Canton, Ohio, a corporation of Ohio Application May 26, 1942, Serial No. 444,526

17 Claims. (01. 219-) This invention relates, as indicated, to methods of forming ferrous alloy heat and oxidation re sistant coatings, facings and articles.

Aluminum has heretofore been added to certain ferrous alloys in appreciable amounts up to about 20% in order to improve the electrical and magnetic properties or'oxidation or heat resistance of such alloys. For these purposes, the amounts of aluminum exceed the amounts usually used for de'oxidation purposes. For electrical uses, the ferrous alloys usually contain in addition to aluminum and iron, nickel, cobalt or tungsten, in varying amounts, For oxidation resistance at elevated temperatures, the alloys usually contain chromium and/or cobalt, in addition to iron and aluminum. For heat resistance, the alloys usually contain chromium and/or nickel and/or silicon, in addition to iron and aluminum.

The following are examples of alloys used as electrical resistors:

Chromium Aluminum The following are examples of Owing to the fact that the aluminum is usually incorporated directly into the molten alloy, as when the molten alloy is still in the ladle, it is usually difllcult to fabricate or forge the alloy into finished products, since the alloys are usually brittle. For this reason, it is preferred, in most instances, to cast the alloys in substantially finished form.

While the cause for this brittleness and difficulty in forging or otherwise plastically deform-- ing the alloy is not definitely known, it is believed to be due, to some extent at least, to the fact that the aluminum, when incorporated in the alloy in the manner described above, forms aluminum oxide inclusions at the grain boundaries, and that these inclusions so interrupt the continuity of the material as to render it brittle in V varying degrees.

We have discovered that this brittleness can be eliminated or minimized to a great extent, and the alloys rendered forgeable and otherwise workable by first producing the ferrous alloys, minus the aluminum, in the form of weld wire or weld rods, and incoporating the aluminum in the fused alloys resulting from the fusion of such weld wire or weld rods, such fusion being usually incident to arc welding or gas Welding. In other words, we propose to start with the ferrous alloys such as described above, but in solid form and devoid of the requisite aluminum content, and then add the aluminum, in the desired proportion, to the pool of.metal resulting from the fusion of the ferrous alloy, the aluminum being preferably added to the fused ferrous alloy simultaneously with the fusion of the latter.

The aluminum may be added to the ferrous alloys in varying ways, among which the following may be mentioned.

Aluminum wire of any desired thickness may be attached to the weld wire or 'weld rod, so as to be fed to the are simultaneously with said ferrous alloy wire or rod. The thickness of aluminum wire will depend upon the percentage of aluminum desired in the finished alloy. This method is particularly desirable in cases where heating equipment, such as oil stills and the like,

are to be faced or coated with the aluminumcontaining oxidated or heat-resistant ferrous alloy. The aluminum wire, in such case, may be (a) Attached to the weld wire or rod by means of suitable clips or other fastening means,

(b) Attached to the weld rod or wire by means of a coating which envelopes both wires, and

which may be an arc welding coating of any well-known type,

which in that case, will be of. tubu form,

(d) In tubular form, enclosing the ferrous alloy, which, in that case, constitutes a core.

The aluminum wire, in all of the above instances, may be of any desired cross-section.

The aluminum may also be incorporated as a powder inside a tube or tubing of the ferrous alloy, which is fed to the are, but in that case, care must be observed to prevent melting of the powder at a greater rate than the ferrous tube or tubing.

Moreover, the aluminum may be incorporated in powder form, in the arc weld coating with which theweld wire or rod is usually provided.

' f of aluminumattached thereto at 3;

Figs. 1, 2, 3 and 4 illustratecross-sectionsfof weld rods embodying our invention.v

- Examples of weld rods embodying. some ofth foregoing ideas are illustrated inthe accompanying drawing, wherein Fig. 1 is a transverse cross-sectional viewofa .wlre 2 new era" Fig. 3'is-a transverse cross-sectional view of a I hollow ferrousalloy weld rod ortubeIi having a core l of aluminum therein, anda, r Fig. 4 is a transverse cross-sectional yiew of a hollow ferrous alloy weld rod or tube 8 having a core 9 of powdered aluminum therein.

rod of the ferrous alloy minus the aluminum to an electric'arc formed between the wire and the article, and simultaneously feeding aluminum 'wire or rod to said are, aluminum being fed in such amount in relation'to said wire or rod as to I form more than 2% of the coating.

3. The method of applying a coating of a heat-resistant ferrous alloy containing aluminum to an article, which consists in feeding a wire or rod of the ferrous alloy minus the aluminum buthaving 'a wir orrod of aluminum attached thereto to an electric are formed between said wires or rods and'the article, the aluminum Other methodsof incorporating the aluminum I;

in the ferrous alloy are by sprayin the aluminum, either as a powder, or as molten aluminum from a spray gun, into thefarc, or by pouring molten-aluminum into the a rc.. In all cases, however, it is necessary to accurately gauge the amount of aluminum added, so as to correlate this amount with the rate at which the ferrous alloy is melted by the arc, and thereby insure that aluminum, in the desired percentage, is presentin the final alloy.

As previously stated, the foregoing methods are also applicable to acetylne or gas welding.

Instead of applying the invention to the facing or coating of articles in the manner described, it may also be used in the formation of heat-resistant articles by casting in molds or dies. In such case, the arc will be formed directly over the mold or die, in ferrous alloy and aluminum permitted to run into such mold or die.-

Facings, coatings and articles formed in this manner exhibit excellent properties, are f er substantially free from brittleness, and are strong, forgeable and otherwise workable. Moreover, by the practice of the present invention, it is unnecessary to resort to melting in or under a vacuum; I

While we are not entirely certain of the reasons for the improvements in the properties of the final deposited ferrous alloys, we believe that this may be partially attributed at least to the fact that theatmosphere about the arc in arc welding as well as about the deposited metal in gas welding is usually a protected atmosphere created by a number of different conditions with which those skilled in this art will probably be familiar, and that this atmosphere prevents the oxidation of the aluminum as it is incorporated in the ferrous alloy. I, I

Various changes maybe made in the details of the methods which havebeen described, withregulated amounts to such .arc, aluminum being fed in such amount in relation to said wire or rod as, to form more than 2% of the coating.

2. The method of applying a coating of a heat resistant ferrous alloy containing aluminum to an article which consists in feeding a wire 01' 1d the molten being in such amount relative to the first-named wire or rod as to form more than 2% of the analysis of the coating. v 1 4. The method of applying a coating of a heat-resistant ferrous alloy containing alumi num to an article-Which consists in-feeding a hollow rod of the ferrous alloy-minus the aluminum, but containing a core of aluminum to an electric are formed between said rod and core and the article, the aluminum being in such amount relative to the rod as to form more than 2% of the analysis of the coating.-

5. The method of applying a coating of a heat-resistant ferrous alloyv containing aluminum to an article, which consists in feeding a rod of the ferrous alloy minus the aluminum, but having a coating of aluminum thereon to an electric are formed between said coated rod and the'article, the aluminum being in such amount relative to the rod as to form more than 2% of the analysis of the coating;

6. The method of applying a coating of a heatresistant ferrous alloy containing aluminum to an article which consists in applying awire or rod -of the ferrous alloy minus the aluminum to the article, progressively melting said wire or rod to form a deposit on the article and simultaneouslyfeeding aluminum in regulated amounts to the molten metal, aluminum being fed in such amount in relation to said wire or rod as to form more than 2% of the coating.

7'. The method of applying a coating of a heat-resistant ferrous alloy containing alumimum to an article, which consists in feeding a of the-coating.

8. A weld rod consisting of a, rod of a heatresistant ferrous alloy, and an aluminum rod rod of the ferrous alloy minus the aluminum, but having an arc welding coating thereon "which contains the aluminum to an electric are formed between said coated rod and the article, the

rod as to form more than 2% of the analysis attached to said first-named rod, the amount of aluminum in relation to the alloy being in excess of 2%.

out departing from the jscope of the invention, r

9. A .weld rod consisting of a heat-resistant ferrous alloy, and a coating of aluminum on said rod, the amount of aluminum in said coating being such that the fusion of the rod'and coating will form a deposit containing more than 2% aluminum. v

10. A weld rod consisting of-a heat-resistant ferrous alloy, and a coating on said rod containing aluminum, the amount of aluminum in said coating being such that the fusion of the rod and coating willform a deposit containing more, than 2% aluminumr 11. A hollow weld rod. consisting of a heat resistant ferrous alloy, and a core of aluminum in said weld rod, the amount of aluminum in said core being such that fusion of the rod and core will form a deposit containing more than 2% aluminum.

12. A- hollow weld rod consisting of a heatresistant ferrous alloy, and a core of powdered aluminum in said weld rod, the amount of aluminum in said core being such that fusion of the rod and core will form a deposit containing more than 2% aluminum.

13. A weld rod comprising a rod of a ferrous alloy, and aluminum associated with said rod in an amount such that when the rod and aluminum'are fused as by welding, the resultant alloy will contain aluminum in an amount in excess of 2%.

14. A weld rod comprising a rod of a ferrous alloy, and aluminum associated with said rod in an amount such that when the rod and aluminum are fused as by welding, the resultant alloy will contain aluminum in amounts from about 2% to about 7.5%.

15. A weld rod consisting of a rod of a ferrous alloy, and an aluminum rod attached to said first-named rod, the amount of aluminum in relation to the ferrous alloy being such that fusion of the two rods will produce a heat-rcsistant ferrous alloy containing from about 2% to' about 7.5% aluminum.

16. The method of applying a coating of a heat resistant ferrous alloy containing aluminum to an article which consists in feeding a wire or rod of a ferrous alloy to an electric arc formed between the wire and the article, and simultaneously feeding aluminum in regulated amounts to such arc, the aluminum being fed in such amount in relation to said wire or rod as to form more than 2% of the coating.

17. The method of applying a coating of a heat resistant ferrous alloy containing aluminum to an article which comprises progressively melting a wire or rod of a ferrous alloy to form a coating of such alloy upon the article, and simultaneously feeding aluminum in regulated amoimts so as to form a part of said coating, the aluminum being homogeneously distributed through said coating and being fed in such amount in relation to said wire or rod as to form more than 2% of the analysis of the coating.

ARTHUR T. CAPE. ANTONE GAXIOLA. 

